1. Field of the Invention
This invention relates to information technology (IT), and more particularly, to a RAID capacity expansion interruption recovery handling method and system which is designed for use by a disk array unit, such as a RAID (Redundant Array of Independent Disks) unit, for providing the RAID unit with a recovery handling function in response to an event of abnormal interruption to an capacity expansion procedure on the RAID unit.
2. Description of Related Art
RAID (Redundant Array of Independent Disks) is a multi-disk storage unit that contains two or more hard disks for providing a very large data storage capacity. A RAID unit is commonly connected in a network system to one or more servers for these servers to store the large amount of data that flow through the network system. Since a RAID unit contains a cluster of independent disks, it allows an interleaved access method that can significantly enhance data access speed, as well as providing a multiple backup function that allows the storage of data to be highly reliable and secured.
In actual applications, the multiple disks of a RAID unit are grouped into one or more clusters, each cluster being used for serving a specific storage purpose, such as email server storage or file server storage. When the network management personnel wants to expand the total capacity of the RAID unit, a new disk can be added to the RAID unit. This task is customarily referred to as a capacity expansion procedure. After the new disk is installed, it requires a set of configuration data about the RAID unit (such as the superblock data) to be duplicated to the newly-added disk.
In practice, however, during the proceeding of the capacity expansion procedure, abnormal power shutoff might occur to the RAID unit, causing the capacity expansion procedure to be abnormally interrupted. In this case, when electrical power is resumed to the RAID unit, the abnormally-interrupted capacity expansion procedure should be started over all again from the very beginning, and not from the checkpoint where the interruption occurred. For this sake, when abnormal interruption occurs to the capacity expansion procedure, the previous process time spent on the abnormally-interrupted capacity expansion procedure is entirely wasted, which would significantly degrade the overall network system performance and serviceability.